Many forms of heavy equipment require chains which have very large load hoisting, or lifting, capabilities. One such field of use for heavy lifting chains is in draglines which are commonly used for removing large volumes of material, such as dirt, loosened ore, etc. Draglines work by dragging a large bucket along the surface to scoop up material and are available in a variety of sizes.
Heavy equipment, in the form of draglines, are some of the most massive mobile equipment produced, with the largest having capacities in excess of 100 cubic yards per bucket load.
The loads on the hoist and drag chains and their links are massive. These loads require the use of specialized chain links made from high strength alloy steels. In addition, these chains and chain links must be designed to endure a tremendous amount of wear. For example, one common failure point for links having a bushing welded thereto to provide a wear surface at the coupling point for adjacent links is the weld.
The structure and operation of a typical dragline requiring such massive and high load carrying chains and links is described in U.S. Pat. No. 6,170,248 which is incorporated herein by reference.
It would be advantageous to provide chain links for heavy equipment, including but not limited to draglines, which are capable of withstanding the high loads imposed thereon, have longer life cycles, and are less prone to failure.